From the past, a working machine has been suggested in which a part of a driving mechanism is electrified. Such a working machine includes a hydraulic pump for hydraulically driving movable portions such as, for example, a boom, an arm, and a bucket, and an AC motor (an electric generator) is connected to an internal combustion engine motor (an engine) for driving the hydraulic pump, whereby an operation of assisting the driving force of the engine, and an operation of charging the electric power obtained by the electricity generation to a storage battery are respectively performed as necessary. For example, in PTL 1, such a hybrid-type working machine is disclosed. In the hybrid-type working machine described in PTL 1, depending on the request power of the hydraulic pump, the distribution of power to be output by the electric generator for assisting the engine is determined, and the power distribution is corrected so that deviation between target revolutions and the real revolutions of the engine is resolved.